<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>runcode</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="Author" content="Sheneyan" />
<script type="text/javascript">
var mh = 30; 
var step = 1; 
var ms = 10; 
function toggle(o){
  if (!o.tid)o.tid = "_" + Math.random() * 100;
  if (!window.toggler)window.toggler = {};
  if (!window.toggler[o.tid]){
    window.toggler[o.tid]={
      obj:o,
      maxHeight:o.offsetHeight,
      minHeight:mh,
      timer:null,
      action:1
    };  }
  o.style.height = o.offsetHeight + "px";
  if (window.toggler[o.tid].timer)clearTimeout(window.toggler[o.tid].timer);
  window.toggler[o.tid].action *= -1;
  window.toggler[o.tid].timer = setTimeout("anim('"+o.tid+"')",ms );
}

function anim(id){
  var t = window.toggler[id];
  var o = window.toggler[id].obj;
  if (t.action < 0){
    if (o.offsetHeight <= t.minHeight){
      clearTimeout(t.timer);
      return;
    }
  }
  else{
    if (o.offsetHeight >= t.maxHeight){
      clearTimeout(t.timer);
      return;
    }
  }
  o.style.height = (parseInt(o.style.height, 10) + t.action * step) + "px";
  window.toggler[id].timer = setTimeout("anim('"+id+"')",ms );
}
</script>

<style type="text/css">
div.xx{border:solid 1px;overflow:hidden;}
div.xx h5{border:solid 1px;border-width:0 0 1px;padding:0;margin:0;height:30px;line-height:30px;cursor:pointer;background:#eee;}
</style>
</head>
<body>
<div class="xx"><h5 onClick="toggle(this.parentNode)">1</h5>
<p>2</p>
<p>3</p>
<p>4</p>
<p>5</p>
</div>
</body>
</html>